Various synthetic wall and roof coverings are known today, such as those formed of elongated molded thermoplastic wall panels that are nailed or screwed to a wall or roof support surface in horizontal courses or rows in partially overlapping relation to each other so as to provide a substantially water resistant, protective layer over the support surface. Such panels, which usually are identically molded, commonly are formed with one or more rows of simulated building elements, such as stone, brick, or shake shingles. Since the panels are identically molded, a panel-to-panel identity can be easily noticed if the panels are not carefully installed. Installation problems particularly occur when installing such synthetic wall and roof coverings about corners of the roof or sidewalls.
Typically, corner moldings are used to join the wall panels at corners of the wall surfaces. In some prior corner moldings, the wall panels must be positioned into abutting relation with a pre-mounted corner molding prior to installation of the wall panel. Such mounting requires precise cutting of the ends of the panels to ensure good installation, which can substantially increase the time and cost of installation. In other known corner moldings, an end of the wall panel is positioned into a side cavity of the corner molding, which can leave unsightly gaps between the corner molding and wall panel by virtue of excessive tolerances.
The continuing need exists for improving the structural integrity of such corner moldings for enhancing efficient and reliable installation of the corner construction for long-term usage. While it is desirable to provide internal vertical support and reinforcing walls that extend inwardly of the front faces of such corner moldings, a problem with such internal walls or reinforcing flanges in plastic injection molded parts is that they can create sink marks on the exposed outer faces of the corner molding due to non-uniform cooling of the molded plastic material at the juncture between the mating walls. Vertical sink marks are a particular problem with corner moldings which have horizontally disposed building elements, typical of simulated hand laid stone or brick. In that case, unlike vertically-oriented cedar shake and the like, the sink marks noticeably cross perpendicularly to the horizontally-oriented building elements.